A ruptured earth(Goddess of victory: Nikke)

Here's a copy and pasted setting summary from Wikipedia

Goddess of Victory: Nikke takes place in a post-apocalyptic future where the Earth was suddenly attacked by extraterrestrial mechanical creatures called Raptures that destroyed everything on the surface, forcing the remaining humans to take refuge underground and establish the Ark, a metropolis ruled by the Central Government. The manufacturers Elysion, Missilis Industry and Tetra Line—owned by Ingrid, Syuen and Mustang, respectively—that compose the Big Three work on converting women and children into powerful obedient soldiers called Nikkes to be used as a weapon to defeat the Raptures and restore humanity on the surface

( mine from here) At some point machines call raptures started to attack Humanity in response Humanity built the ark Underground Safe Haven the inadvertently also created the outer rim a part of the Ark which pretty much where they send all their non-desirables and created female soldiers called Nikkes to fight them to take it back the surface by the commanders(all humans) who lead Nikke squads

(The main character is kind of a generic dating Sims protagonist so if you want to add any actual backstory go ahead to make him your own character or you can create your own character )( I honestly don't know if they've said the reason why raptures even exist in the game yet but the game itself is kind of fun and the story is actually really interesting although I can get rather sad sometimes . they're trying to defeat the queen of the raptures I don't think she's been seen in the game yet)( to be honest I really don't know why it's just women and children that can be made into nikkes when I was looking it up it said between ages of 10 and 25 when they are turned in to nikkes. Concerning some of the nikke ages it says 10 to 25 but I think that's just for the conversion process I don't actually know how old each one of them is due to them being on a mechanical body I mean if any of them with young appearances disturbing just age them up all of them are good looking )